[PATCH] D47143: [NewGVN] Do not treat LoadExpressions with differing nonnull as equal.

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

For reference, another bug relating to NewGVN + Simplify is https://bugs.llvm.org/show_bug.cgi?id=34093. In that case it's not a matter of metadata, but an equivalence that was established based on predicateinfo is assumed to hold prior to the corresponding ssa.copy, resulting in incorrect simplification.

https://bugs.llvm.org/show_bug.cgi?id=31792 is not a miscompile but rather a missed optimization. GVN knows that two GEPs reference the same base, but simplification doesn't.

I'm finding it hard to put these three issues under one umbrella. They all need some kind of additional interaction with simplification to be resolved, but the specifics seem to be quite different in each case, it's not just a matter of a single flag.


https://reviews.llvm.org/D47143